Inventory levels are a cost of business and must be managed in a cost efficient manner. Inventory level controls and inventory replenishment techniques are implemented to optimize inventory. There are various types of such controls and techniques. Some inventory controls are reactionary in nature because they operate relative to perceived shortages in existing inventory. Some inventory controls are preemptive in nature because they try to anticipate demand based on known criteria. Some inventory replenishment techniques are configured to ensure that orders can be immediately satisfied by keeping required items in stock during the replenishment cycle. The degree of success in implementing such controls and techniques is at least partially dependent upon the efficiency in which warehousing operations are run, including optimizing the storage space and item handling time as items move in and out of a warehouse.